This Spider Hides Like Bird Poop

You might be freaked out by spiders in and around your home. You may do those karate master chops when you inadvertently walk thru a spider web. The truth is that in most case the spider is more freaked out by you. Spiders, in most cases, are very often the hunted. They are the prey of all types of animals. For this reason spiders do quite a bit of work to stay hidden and out of sight.

But When You Can’t Get Out of Sight?

The orb-web spider’s silver body and the white, silken, disclike decoration on its web give it an uncanny resemblance to bird droppings. The spiders may use this disguiseto avoid being captured by predatory wasps, researchers say.

“These predators usually will form a search image to hunt for spiders, and [they] usually will not be interested in bird droppings,” said lead study researcher I-Min Tso, a behavioral ecologist at the National Chung-Hsin University in Taiwan. [See Photos of Spiders Masquerading as Bird Droppings]

Masquerading is a phenomenon in which an animal’s body color and shape mimic an inanimate object. The body coloration of many web-building spiders strikes a balance between being attractive to prey and hidden from predators. As part of their disguises, many spiders also add colorful decorations to their webs, called stabilimenta, made from prey carcasses, egg sacs, plant matter or silk.

For the orb-web spider (Cyclosa ginnaga), those silken web decorations could make its bird-feces costume even more believable. “Since orb-web spiders can make silks, such [an] adaptation may facilitate the bird-dropping masquerading of these spiders,” Tso told Live Science.

To test whether the fecal disguise was effective, the scientists measured the color contrast between the spider’s body, its web and actual bird droppings, all against a background in nature. The results showed that the spider bodies were indistinguishable from their webs and from the bird droppings, as viewed by wasps, the researchers said.

Then, the researchers blackened either the spiders’ bodies and web decorations, just the disclike web decorations or just their bodies, and observed how often wasps attacked the arachnids. The wasps were more likely to attack a spider when only its decoration was blackened, suggesting that the spiders were, indeed, using their body and decoration as a disguise.

So, the next time you see some bird poop you might take a little closer look, but not that close, to see if it is poop or an orb web spider. You might get surprised, or just a close look at some bird poop.